Aracnoid granulations provide the pathway for drainage of cerebrospinal fluid from the subarachnoid space into the dural venous sinus system. They frequently produce small, well-defined indentations on the inner table of the calvarium that are easily recognized on radiographic studies and gross examination of the skull. We report a series of four giant cystic arachnoid granulations presenting as large "destructive" osteolytic lesions that required surgical exploration. The cysts were filled with cerebrospinal fluid and were delineated by a thin fibrous wall that contained peripheral clusters of arachnoid cells. We discuss the pathologic and radiographic differential diagnosis of osteolytic skull lesions and present a hypothesis regarding the formation of giant cystic arachnoid granulations.
- arachnoid granulations
- Pacchionian granulations
ASJC Scopus subject areas
- Pathology and Forensic Medicine